Atrial fibrillation (AF) is the most common cardiac dysrhythmia and occurs in 3.3%-10% of emergency admissions. It is frequently quoted for people over the age of 75, but the cases of AF in young subjects without structural heart disease are also increasing, therefore, leading to the evaluation of "lonely atrial fibrillation" as a new challenge for the clinician. The first diagnosis and treatment often occur in the emergency room and the emergency physician has therefore to evaluate the initial step towards the therapeutic decisions. Although international standard guidelines are available, AF treatment in the Emergency Department (ED) is still heterogeneous in terms of the management strategy chosen. There are two main strategies for the management of AF: rate and rhythm control. Moreover, antithrombotic treatment is pivotal in AF to prevent cardioembolic stroke and it is considered a primary objective after an accurate assessment of antithrombotic treatment risks and benefits. The introduction of innovative echocardiographic approach, directly in ED, seems to improve the management and risk stratification of patients with AF.